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Can Somebody explain epsilon delta proofing?
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by
 
on 2007-09-06 18:51:28 |
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Yeh, never learned this in my IB Higher Level Mathematics in high school and now they teach it in College and it's something the class doesn't know. I have to learn this myself. Dumb teacher never bothered to explain I know this much: Using the stuff lim f(x) = L x->c 0 < |x-c| < d |f(x) - L| < E So let's say f(x) = 2x and the given E = 0.06 and lim f(x) x->1 and we were asked to find d > 0 Basically this is how I interpreted it (tell me if this is correct): We are trying to find the d > 0 to satisfy 0 < |x-c| < d and so to find d > 0 I used |2x-2| < (3/50)E getting E: (50/3)|2x-2| < E and now we use |x-c| (which by sub. we get |x-1|) and find out how it relates to (50/3)|2x-2| so we can factor a 2 and end up with a (100/3)|x-1| ************(oh great maybe I shouldn't have divided by (3/50) in the first place?)*************** so we can now choose that d=(3/100)E placing it in the long inequality gives 0 < |x-1| < (3/100)E and so is 3/100 the answer? I'm lost, did I even do this correctly?  |